Yellow Weather Warnings have been issued for thunderstorms in Somerset on Sunday by the Met Office, as a plume of warm air will raise temperatures and increase the risk of thundery showers.

The area of high pressure which has been responsible for the last couple of weeks of settled weather for much of the UK will drift away towards Scandinavia, allowing a plume of warmer, humid air from the south to influence the weekend weather for much of the UK.

Temperatures will begin to climb from Friday as the warmer air pushes in from the south, bringing with it the chance of some evening and overnight showers in the southwest of England and southern Wales.

As this warmer air pushes further north and east through the weekend, temperatures will rise, triggering widespread thundery showers by Saturday afternoon and again on Sunday. These will bring the chance of hail and gusty winds for some places, as well as torrential downpours for a few. This will be the first meaningful rainfall for many places across the UK for several weeks. As is often the case, many places will either miss the worst of any thunderstorms, some staying dry altogether, just a few locations catching the intense downpours.

A Yellow Warning for thunderstorms has been issued, covering Wales and a large area of southern and central England from 1400 to 2100 on Saturday. The warning highlights potential disruption to travel, the chance of power cuts and the possibility of very localised flooding from the heaviest showers.

Met Office Chief Meteorologist Frank Saunders, said: “Temperatures will increase into the weekend with a peak of 31°C expected on Saturday in central and southeast England. As the heat builds from the south, thundery showers will develop through Saturday afternoon and while not everyone in the warning area will see the heaviest showers, or even any rain at all, some will bring heavy thundery downpours. With intense showers there is a risk of surface water flooding which could cause some disruption – the very dry, baked ground may not help in that respect.”

A second Yellow warning for thunderstorms has been issued for Sunday between 1200 and 2100, covering a large area of the UK including parts of Wales, England, Northern Ireland and Scotland. Frank added: “The heat will last for a few more days at least, Sunday will see 30°C again in parts of southern UK and the risk of thunderstorms also spreads more widely across the UK – particularly western and central areas – with heavy downpours again brining the risk of thunder, hail and gusty winds. As well as higher daytime temperatures, overnight temperatures will also climb with some locations not getting below the mid-teens °C overnight.”

East and northeast Scotland are likely to be the main exception to the change in conditions, with an easterly breeze possibly keeping temperatures more subdued with cloud likely to persist for some. Some coastal areas will be cooler than the peak figures further inland, with sea breezes off the North Sea preventing the highest temperatures building on immediate coastlines.